09__Development.md

title
Development Techniques

Automatic Code Reloading

Restarting an application manually after every code change is both slow and painful. It can easily be avoided by using a tool for automatic code reloading.

Shotgun

Shotgun will actually restart your application on every request. This has the advantage over other reloading techniques of always producing correct results. However, since it actually restarts your application, it is rather slow compared to the alternatives. Moreover, since it relies on fork, it is not available on Windows and JRuby.

Usage is rather simple:

gem install shotgun # run only once, to install shotgun
shotgun my_app.rb

If you want to run a modular application, create a file named config.ru with similar content:

require 'my_app'
run MyApp

And run it by calling shotgun without arguments.

The shotgun executable takes arguments similar to those of the rackup command, run shotgun --help for more information.